Efforts this year will be directed toward electrolyte studies of postmortem, "normal" human lenses and cataractous lenses. In view of the prevalence of cation shifts in human cataracts and the recently reported relationship between potassium concentration and protein synthesis, our aim is to focus on properties of the cation transport system of postmortem and cataractous lenses. Prior to employing the usual tracer approach involving flux measurements of K ion, Na ion and Ca ions, the physiologic state of lenses will be assessed by monitoring the potential. The time dependent changes in potential during subsequent culture together with comparable data from normal lenses should be useful in differentiating changes brought about by cryoprobe extraction from those brought about during cataractogenesis. To the extent that such lenses can be maintained physiologic or in dynamic equilibrium in culture, cation transport properties will be characterized by flux analysis and electrolyte measurements. With respect to calcium, the fluxes of which prove difficult to interpret due to high binding affinities, the mechanism of its regulation in the lens will be approached initially by assaying lens homogenates for a Ca ions -ATPase.